A continuous glucose monitor (CGM) can measure several glucose concentrations over a period of time. Examples of CGM's can be an electrochemical sensor implanted in the subcutaneous layer, an ex vivo electrochemical sensor that measures extracted physiological fluid, or a non-invasive glucose sensor using reflected infrared light, as described in U.S. Pat. Nos. 6,348,274; 5,804,048; and 6,574,490. One of the potential benefits of a CGM is the ability to notify a person with diabetes of a hypoglycemic event. In general, a person with diabetes would like to reduce the incidence of hypoglycemia to mitigate the risk of incurring serious short-term harm (e.g., loss of consciousness, coma, and death) and long-term harm (e.g., cardiac disease, retinopathy, and kidney disease). A hypoglycemic alarm can potentially reduce the amount of time that a person with diabetes is in the hypoglycemic state because appropriate therapeutic action (e.g., consume glucose or reduce insulin intake) can be immediately initiated when the alarm is triggered.